Inactivation by solar photo-Fenton in pet bottles of wild enteric bacteria of natural well water: Absence of re-growth after one week of subsequent storage

Iron photo-assisted inactivation of wild enteric bacteria (total coliforms/E. coli and Salmonella spp.) was carried out in water from the Sahelian wells having different pH (W1:4.9 and W2:6.3) and a natural iron content of 0.07 mg/L. We evaluate the efficiency of the disinfection on different systems containing both or only one Fenton reagent (H(2)O(2)/Fe(2+)): (i) H(2)O(2)/Fe(2+)/hv, (ii) Fe(2+)/hv. (iii) (2)O(2)/hv, and (iv) only light irradiation (hv) at lab and field scale. Generally, 0.6 mg/L of Fe(2+) and/or 8.5 mg/L of H(2)O(2) were used in the Fenton reagent. The systems H(2)O(2)/Fe(2+)/hv and H(2)O(2)/hv led to total inactivation of Salmonella and E. coli. The natural iron content (0.07 mg/L) was enough to drive an efficient photo-Fenton process leading to total bacterial inactivation. Our results show that: (i) the iron salt present in Sahelian water is enough to perform a photo-Fenton disinfection of drinking water when adding H(2)O(2), (ii) addition of external iron salts at near neutral pH has no additional effect on the bacterial photo-Fenton inactivation process. After one week of storage, no enteric bacteria re-growth was observed in treated waters. Mechanistic suggestions are presented to explain the observed results.